The present invention is directed towards electrical power source free tamper detection sensors and, more particularly, sensors that detect and record sufficient mechanical change in the packaging of, or other protective enclosure of, items such as integrated circuits or electronic systems to indicate tampering therewith.
The prevention of unauthorized handling, or the removal from rightful custody, of personal, corporate, or military items, components, systems or other entities, or the illicit obtaining of information therefrom or thereabout, particularly expensive electronic goods or electronic devices that contain sensitive data, has become increasingly important. This growing importance of such physical security for those entities against such tampering comes about as the numbers of such entities has grown, and as their economic value and the competitive value of sensitive information often contained therein has also increased. The ongoing trend of storing vast amounts of personal and business data and software in a computer hard disc drive, a portable memory device, or other electronic systems makes theft and tamper prevention all the more important. Computers, personal digital assistants (PDAs), cell phones, portable data storage devices, and smart cards, are increasingly available in the home and in the business place. Military systems increasingly contain sensitive hardware and algorithms that cannot be permitted to fall into the hands of a foreign government, or agents thereof, that might attempt to reverse engineer a critical military system for its own use.
Even larger systems, such as desk-top computers or hardware systems that cannot easily be removed from a home or facility, are also susceptible to theft or compromise: there is a likelihood that valuable information or sensitive information bearing internal components such as non-volatile memory chips, computer hard drives, programmable gate arrays, or application specific integrated circuits may be removed after the exterior cover thereof has been removed. Most such thefts are never solved, and the property is rarely recovered. Therefore there is a need to protect certain entities, such as a computer or other electronic systems, from being opened to remove sensitive components or to recover valuable data including but not limited to security encryption keys and computer algorithms.
Tamper protection for systems falls into at least three categories; tamper-evident packaging; packaging that is difficult to remove without destroying the protected device; and sensors to detect intrusion to allow a system to erase sensitive data or to destroy critical hardware in the event of tampering. Tamper-evident packaging schemes are limited to low cost devices or low importance data, and do not provide any protection in the situation in which an entire system can be stolen. Anti-tamper coatings or housings that are difficult to remove without destroying the components contained within the housing also do not protect data stored within the enclosure as the data can be recovered from damaged components. Sensors that allow a system to destroy critical data or disable critical components often need electrical power such as from a battery in order to operate. Different types of sensors, including switches to mechanically detect the removal of a lid, optical sensors to detect light, and fabrics containing wires that must be cut to access a component, always require electronics hardware that must be electrically powered to record the tamper event. There is thus a security risk in that a clever tamperer, such as a person skilled in “reverse engineering” or “hacking”, may disable the sensor before the system records the tamper event and responds. There is thus a need for a tampering sensor that can record a tamper event in the absence of applied electrical power. Such a sensor is often made even more useful if it can destroy critical data, such as, but not limited to, an encryption key, in the absence of applied power.